Apparatus for heat sealing cartons



Aug. 6, 1969 A. H. T. CHIN 3,462,916

5 Sheets-Sheet 1 YNVENTO ARTHUR H. T CHIN Bu; a OQZ/Qw 1 ATTORNEYS Aug.26, 1969 A. H. T. CHIN 3,462,916

APPARATUS FOR HEAT SEALING CARTONS Filed July 18, 1966 5 Sheets-Sheet 5IINVENTOR, ARTHUR H. T. CHIN BY w z wwz ATTORNEYS United States Patent3,462,916 APPARATUS FOR HEAT SEALING CARTONS Arthur H. T. Chin, CastroValley, Calif., assignor to Fibreboard Corporation, San Francisco,Calif., a corporation of Delaware Filed July 18, 1966, Ser. No. 565,972Int. Cl. B65b 7/20, 51 /20,' F24h 3/04 US. Cl. 53375 24 Claims ABSTRACTOF THE DISLQSURE This invention relates to an apparatus and method forheat sealing cartons and more particularly relates to an apparatus andmethod for applying heated air to selected portions of adhesivelytreated carton flaps and sealing them together.

The packaging of butter, ice cream and like perishables generallyrequires a mechanical lock, conventional glues or a carton overwrap toassure carton integrity and to prevent spoilage of the product retainedtherein. The application of heat to the cartons flaps to effect sealedend closures gives rise to a number of problems which are not totallysolved by conventional apparatus and methods. For example, suchapparatus and methods are generally arranged to conduct or otherwiseconvey a substantial amount of heat whereby the packaged product becomescontaminated or otherwise damaged. Also, certain adhesive materials maybe damaged or lost due to such high heat concentrations. In addition,the carton oftentimes becomes scorched or otherwise defaced due to ahigh heat concentration at portions thereof. Also, a tight end closureis not always effected to assure a high degree of structural integrityto the carton for shipping and like purposes.

The instant invention provides an apparatus and method adapted toovercome such difliculties and particularly adapted for the packaging ofperishables, such as ice cream and butter by using hot air for cartonsealing purposes. Attention is drawn to United States Patent No.3,248,843 and United States patent application Ser. No. 457,893, bothassigned to the assignee of this application, which disclose apparatusand methods particularly adapted to employ air maintained atsubstantially high temperatures and volumes to heat seal adhesivelytreated carton flaps.

This invention, on the other hand, is capable of utilizing heated air ata substantially low volume and temperature thus requiring less powerinput to the heating means employed to heat the air. The nozzle baremployed to subject the carton flaps to hot air is further adapted toconduct heat directly to the carton flaps. The heat may be thusconcentrated at selected areas of the carton flaps to increase sealingrates, also eliminate scorching or other types of defacing of paperboardsurfaces and prevent damage to the adhesive utilized. Thus, carton endclosures may be sealed rapidly, heat losses are minimized and little, ifany, heat is transferred to the product contained in the carton.

An object of this invention is to provide an apparatus and methodwhereby a low volume of heated air may be utilized to effect aneificient carton seal expeditiously and economically withouttransferring appreciable amounts of heat to the cartons contents orcausing carton defacing.

Another object of this invention is to provide an elongated and narrownozzle bar means in a heat sealing apparatus arranged to efficiently andrapidly seal adhesively treated carton portions together.

A further object of this invention is to provide an apparatus for heatsealing carton flaps comprising a nozzle bar and flap control bar meansadapted to be arranged for sealing various carton flap arrangements.

Further objects of this invention will become apparent from thefollowing description and accompanying drawings, wherein:

FIG. 1 is a view with parts broken away illustrating an apparatusembodying novel aspects of this invention as it would appear during acarton sealing operation;

FIG. 2 is an end elevational view of a heat sealing means employed inthe apparatus illustrated in FIG. 1;

FIG. 3 is a side elevational view of the heat sealing means illustratedin FIG. 2 with portions thereof broken away for clarification purposes;

FIG. 4 is a cross sectional view taken in the direction of arrows 4-4 inFIG. 2;

FIG. 5 is a view taken in the direction of arrows 5-5 in FIG. 1 withparts broken away for clarification purposes;

FIG. 6 is a view taken in the direction of arrows 6-6 in FIG. 1 withparts broken away for clarification purposes;

FIG. 7 is a view illustrating an attachment for a flap hold-down baremployed in the apparatus of FIG. 1;

FIG. 8 is another embodiment of a heat sealing means of this invention;and

FIG. 9 illustrates typical carton end flaps which may be sealed pursuantto the teachings of this invention.

Referring to FIG. 1, the apparatus embodying novel aspects of thisinvention comprises a conveyor means 20 having spaced lugs 21 attachedto continuous chains thereof. The conveyor means is arranged for movinga conventional carton C along a linear path P in the direction of theillustrated arrow. In actual practice, conveyor speeds of from 30 tof.p.m. have been successfully employed. Referring briefly to FIG. 9, thecarton may comprise adhesively treated major flaps F and F and minorflaps F and F The term adhesive as used herein should be understood tomean any pie-applied fuseable coating adapted to be activated by heatfor sealing paperboard or like panels together. For example, suchadhesive may constitute a heat scalable wax, polyethylene, polyvinylchloride or the like. The carton may constitute paperboard or othersuitable packaging material either partially or totally coated with suchan adhesive.

The flaps are suitably arranged to be folded into position byconventional flap folding means (not shown), preferably mounted in astationary manner in the apparatus. A stationary hold-down bar means 22is arranged over the carton to urge it downwardly, as more clearlyillustrated in FIG. 6. The lower, slanted surface of the hold-down baris preferably arranged to make only a line contact with the carton toprevent undue scuffing thereof.

A flap control bar means 23 is arranged to position and hold flap Fsubstantially in a fixed plane during such carton movement. As moreclearly illustrated in FIG. 6, a tapered surface 23a of the flap controlbar is preferably arranged within an angle A of from 5 to 20 relative toa vertically disposed plane to "correctly position flap F It should befurther understood that surface 23a can be arranged in a tapered mannerso as to gradually close flap F when it moves through the heat sealingmeans. The hereinafter explained nozzle bar means could be likewisemodified in a tapered manner to facilitate a gradual closing of thecarton flaps.

The flap control bar is associated with adjusting means (FIG. 7)comprising spaced extensions 23b and 23b, secured thereto to selectivelyvary angle A. The adjusting means, preferably located at each end of theflap control bar, are identical and thus identical numerals accompanylike elements. The numerals depicting elements included in the assembledadjusting means located leftwardly in FIG. 7 are accompanied by a primesymbol however.

Extension 23b has an aperture suitably formed therein and arranged toreceive pin 230 which mounts trunnion 23d. The trunnion preferablycomprises a threaded post 23a arranged to extend through an apertureformed in a stationary bar 23 and secured thereto by a nut 23 Adjustmentscrews 23g and 2311 are suitably threaded in bar 24 to permit rotationof flap control bar 23 about the axis of pin 23c and thus adjustment ofangle A. For example, if it is desired to lessen angle A (FIG. 6) screws23/1 and 23h would be extended a predetermined amount and screws 23g and23g retracted a like amount. It should be noted that the ends of suchscrews are preferably rounded and merely abut flat outer surfaceportions of extensions 23b and 23b.

Referring again to FIG. 1, L-shaped braces 25 and 26 are secured to thestationary bed of the machine. Bar 24, supporting adjustable flapcontrol bar 23, is preferably secured to brace 25 by a bolt 27. Thebraces are further arranged to support carton hold-down bar 22 by meansof suitably arranged attachment means 28 and 29. A heat sealing means 30is attached to the machine to heat seal flaps F and F together as willbe hereinafter more fully explained. The heat sealing means comprises ahousing 31 attached to the bed of the machine by an inverted L- shapedplate member 32 (FIG. The housing preferably constitutes a metallicconstituent, such as aluminum or bronze, constructed to conduct heatparticularly through the nozzle portion thereof.

One or more bolt and spacer arrangements 32a may be arranged tothreadably secure a side wall of housing 31 to member 32 in the mannershown. In turn, an adjusting means, comprising a bolt 32b, preferablyarranged at each end of member 32, secures a horizontally disposedportion of member 32 to a plate 33, detachably secured to the bed of themachine. Thus, rotation of bolts 32b and 32b will function to movehousing 31 in a vertically disposed plane. The adjusting means furthercomprises screws 32c and 32d, threadably secured to such portion andarranged to selectively vary an angle B between such verti callydisposed plane and a vertically disposed axis of housing 31 (FIG. 5) forpurposes hereinafter explained.

A spherically shaped washer 322 is preferably arranged between the headof bolt 32b and member 32 to facilitate such adjustment. For example, ifit is desired to lessen angle B, screws 32c and 32c (FIG. 1) would beextended and screws 32d and 32d would be retracted from member 32. Asabove mentioned, it is preferred to employ an adjusting means at eachend of member 32 for stabilization purposes. However, in certain machineapplications a single adjusting means could be employed. Correspondingelements of the second adjustment means (illustrated in assembled form)are depicted by like numerals accompanied by a prime symbol Referringnow more particularly to the construction and arrangement of housing 31of the heat sealing means illustrated in FIGS. 2-5, a closure plate 31ais detachably secured to the bottom thereof to enclose a preheatingchamber 31b. The air is communicated to chamber 31b via conduit 31c andis thereafter permitted to flow through an elongated opening 31d. Theair is preheated due to contact with internal heated surface portions ofmetallic housing 31.

A conventional pump 34, rated at 2-15 c.f.m. of air and set at 2-10p.s.i., for example, may be utilized to supply the incoming air viaconduit 310 (FIG. 5). Elongated opening 31d communicates with aplurality of slots 31e forming fins therebetween, radially arrangedabout a removable and cylindrically shaped heating means or cartridgeheater 31 Heater 31 has been removed from housing 31 in FIGS. 2-4 forclarification purposes. A Chromolox C 505 heater rated at 1100 watts and240 V. AC. and also a heater rated at 525 watts and V. AC. have beenused successfully.

The slots are further arranged to communicate with a nozzle bar meanscomprising a plurality of radially eX- tending and drilled passages 31garranged intermediate tapered first and second side surface portionsthereof and may be arranged within an angle C selected from a range offrom 0 to 20 (preferably 5 to 15). As above explained, the thickness ofthe nozzle bar means may be varied along the length thereof to effect agradual losing of the carton flaps if so desired for certain cartonsealing applications. Such passages are further arranged to communicatethe air heated by heater 31 to drilled orifices 31h formed in suchsurface portions and arranged in substantial parallel relationship to atop surface portion of the nozzle bar means whereat the side surfaceportions terminate. The orifices are preferably arranged to impart theheated air directly to opposed surface portions of adhesively treatedflaps F and F (FIG. 6).

It should be understood that a greater or lesser number of such orificesmay be employed and arranged in selected patterns on the nozzle barmeans different from that shown. For example, such orifices could beformed on only one of the first and second surface portions of thenozzle bar means. In addition, it has been found that carton C, thenozzle bar means and flap control bar 23 may be arranged to permit theheated air discharged from orifices 3111 to cause the adhesivepreapplied to flap F and/or F to be formed into selected patterns. Forexample, the nozzle bar means in FIG. 6 could be rotatedcounter-clockwise and flap control bar 23 moved leftwardly to effect aline contact between the parallel edges of the top surface portion ofthe nozzle bar means and flaps F and F Such an arrangement would preventthe heated air discharged from orifices 3111 from moving upwardly, abovethe nozzle bar means. Such air would be forced downwardly to cause thepre-applied adhesive into a bead-like configuration adjacent the freeedge of flap F and the juxtaposed portion of flap F As clearlyillustrated in FIGS. 2 and 5, a conventional heat sensing means 311',such as a Fenwal 17202-0 thermoswitch or thermostat, is preferablyattached to housing 31 to have the temperature of the heated airconducted thereto via narrowed portions of the housing to constantlycontrol such temperature preferably within a range of from to 600 F. Aconventional control means 35, schematically illustrated in FIG. 5, maybe utilized for automatically controlling the heat output of heatingmeans 31 The tapered first and second portions of the nozzle bar meansare preferably arranged to abut the portions of the carton flaps to besealed (illustrated in spaced relationship in FIG. 6') during passage ofthe carton through the heat sealing means.

Such an arrangement permits the heating efiects caused by the airdischarged via orifices 3111 to be supplemented by the heat conducted tothe sealed flap portions through the metallic nozzle bar means. The finsarranged to form slots 31e are constructed and arranged to heat andmaintain the nozzle bar means at a temperature which is substantiallythe same as the temperature of the air emitted from nozzles 3171. Theflaps may be held in close proximity to each other to effect a rapidseal due to this atrangement which permits heat, at a substantiallyconstant temperature, to be concentrated at the carton portions to besealed. Also, the low pressure air further functions as a lubricant toprevent sloughing-olf of the pre-applied adhesive.

Once the adhesively treated carton flaps are subjected to heat via thenozzle bar means, conveyor 20 continues to move the carton pastcompression means 36 (FIG. 1), preferably in the form of an endlessbelt, to rapidly effect a tight seal, i.e., no elaborate sealing orcooling means need be employed to seal the carton due to the low sealingtemperature employed. Two such belts are preferably employed to slightlycompress the carton therebetween to effect such sealing. Suchcompression means could also comprise suitably arranged compression barsor the like. It should be noted that constructions and arrangementssubstantially identical to those described above are also employed inparallel relationship on the opposite side of the machine to thussimultaneously effect an end closure at each end of the carton. Suchcompact arrangements differ from conventional ones wherein ratherlengthy sealing means for effecting carton end closures are positionedin series.

FIG. 8 illustrates a modified form of the heat sealing means. Likenumerals, accompanied by a prime symbol depict corresponding structuresincluded in the first described heat sealing means embodiment. A closureplate 31a is arranged to enclose a preheating chamber 31b. Elongatedopening or slot 31d communicates with radially extending slots 312' andpassages 31g which in turn communcate air to orifices 31h. Heater 31f isarranged to have a portion thereof directly heat the air passing throughpassages 31d.

The following method is preferably employed to secure opposed cartonportions together (in this instance flap F to F as illustrated inFIG. 1. Conveyor 20 is arranged for moving carton C along linear path Pduring which movement control bar 23 is arranged for positioning andholding flap F in substantially the same plane during movement throughheat sealing means 30. As more clearly illustrated in FIG. 6, theapparatus is further arranged for holding flaps F and F in closeproximity to each other on each side of the nozzle bar means. Heated airat a low pressure, preferably from 1 to p.s.i., is discharged fromorifices 31h and imparted directly onto selected portions of theadhesively coated flaps F and F As above mentioned, although the flapsare illustrated as being slightly spaced from the nozzle bar means inFIG. 6, it should be understood that in actual practice it is preferredto maintain the flaps in substantial contact with the nozzle bar means.Thus, the nozzle bar means may be utilized to perform a two-fold heattransferring function, i.e., discharging heated air via orifices 31h andconducting heat therethrough to the flaps. Compression means 36 arearranged for compressing the flaps together to form carton end closures.

In actual practice, a temperature setting of from 400 to 480 F. forheater 31f was found to efliciently heat the air utilized for thesealing of a carton coated with polyethylene. During such application,conveyor means was set at 82 feet per minute to convey approximately 70cartons per minute through the heat sealing means. Eflicient seals wereobtained when the conveyor speeds were varied within a range of from 46feet per minute to 117 feet per minute with the temperature settingbeing maintained within a range of from 440 to 480 F. The air supplyutilized was rated at approximately 6 cubic feet of free air per minuteand maintained at approximately 2 to 3 p.s.i.

I claim:

1. An apparatus for sealing opposed adhesively treated flaps of a cartontogether comprising conveyor means for moving said carton along a linearpath, control bar means arranged in substantial parallel relationship tosaid linear path and having a surface formed thereon for positioning andholding one of said flaps during carton movement by said conveyor meansand a heat sealing means comprising a housing having an elongated andnarrow metallic nozzle bar means arranged thereon in substantialparallel relationship to said linear path, said nozzle bar means havingfirst and second fiat surface portions terminating at an edge thereof,said first surface portion positioned in close juxtaposed relationshipto said control bar means to have said one flap maintained insubstantial contact with said first surface portion and the surface ofsaid control bar means, said nozzle bar means further comprising aplurality of orifices formed in at least the first surface portionthereof and passage means formed therein for communicating heated air tosaid orifices and heating means operatively associated with said nozzlebar means for conducting heat through metallic portions thereof and forheating air communicated through said passage means whereby the adhesiveon said one flap contacting the first flat surface portion of saidnozzle bar means is simultaneously activated by heat conducted throughsaid nozzle bar and by said heated air.

2. The invention of claim 1 wherein a plurality of said orifices areformed in each of said first and second surface portions, each one ofthe orifices formed in said first surface portion arranged tocommunicate directly with an orifice formed in said second surfaceportion.

3. The invention of claim 1 further comprising holddown bar meansarranged over and in juxtaposed relationship to said nozzle bar meansfor urging said carton towards said nozzle bar means, said nozzle barmeans further arranged to extend substantially vertically upwardlytowards said hold-down bar means.

4. The invention of claim 1 wherein said first and second surfaceportions of said nozzle bar means are arranged to taper towards eachother and wherein the included angle therebetween is from 5 to 20*".

5. The invention of claim 1 wherein a second of said heat sealing meansis arranged on a side of said apparatus opposite to a side whereat thefirst-mentioned heat sealing means is arranged.

6. The invention of claim 1 further comprising compression meansarranged adjacent to said nozzle bar means for receiving cartonstherefrom and compressing said flaps into sealed relationship.

7. The invention of claim 1 wherein said housing comprises a chamberformed therein, and said heating means comprises a removable heatingmeans inserted into said chamber and arranged to heat air in saidchamber and to conduct heat to said nozzle bar means, said chamberfurther arranged to communicate with said passage means.

8. The invention of claim 7 further comprising temperature sensing meansassociated with said housing adjacent to said chamber and operativelyassociated with said heating means for controlling the heat outputthereof.

9. The invention of claim 1 further comprising means adjustably mountingsaid housing in said apparatus.

10. In an apparatus comprising heat sealing means for heat sealingopposed, adhesively treated portions of carton flaps together, a housinghaving a chamber formed therein, a nozzle bar means having a pluralityof apertures formed therein for discharging heated air therethrough,heating means arranged in said chamber, a plurality of fins constructedand arranged in said chamber to substantially surround and contact saidheating means and a plurality of slots formed between said fins andarranged to communicate air to said apertures after said air has beenheated by said heating means and means for applying pressure to saidflaps to seal them together.

11. The invention of claim 10 wherein said housing, including said fins,is further constructed and arranged to conduct heat from said heatingmeans to said nozzle bar means to heat and maintain the nozzle bar meansat a temperature which is substantially the same as the temperature ofthe air discharged from said apertures.

12. In an apparatus comprising a heat sealing means adapted to heat sealopposed, adhesively treated portions of carton flaps together, theinvention comprising an elongated and narrow metallic nozzle bar meanshaving at least one surface formed thereon, a plurality of aperturesformed in said surface and passage means formed in said nozzle bar meansarranged to communicate heated air to said apertures, a flap control barclosely juxtaposed and parallel to the surface of said nozzle bar meansto hold one of the carton flaps in substantial contact with said surfaceand heating means operatively assocated with said nozzle bar means forsimultaneously conducting heat therethrough and for heating air in thepassage means thereof whereby said one carton flap is subjected to acombination of heat conducted through said nozzle bar means and heatedair communicated through said apertures.

13. The invention of claim 12 further comprising adjusting means formoving said flap control bar to selectively vary the inclination thereofrelative to the surface of said nozzle bar means.

14. The invention of claim 13 wherein said flap control bar is pivotallymounted in said apparatus and said adjusting means comprises at leastone screw means for selectively pivoting said flap control bar to varythe inclination thereof.

1-5. The invention of claim 12 further comprising holddown bar meansarranged in juxtaposed relationship to said nozzle bar means for urgingsaid carton towards said nozzle bar means.

16. The invention of claim 15 further comprising adjusting meansarranged for moving said nozzle bar means in a vertically disposedplane.

17. The invention of claim 14 wherein said adjusting means is furtherarranged for moving said nozzle bar means to selectively vary the anglebetween said vertically disposed plane and a vertically disposed axis ofsaid nozzle bar means.

18. The invention of claim 12 wherein said nozzle bar means comprisesfirst and second fiat surfaces arranged to taper towards each other andwherein the included angle therebetween is sealed from a range of from5" to 19. The invention of claim 18 wherein a plurality of saidapertures are formed in each of said first and second flat surfaces.

20. The invention of claim 12 wherein said heat sealing means furthercomprises a housing and said heating means is removably mounted therein.

21. An apparatus for heat sealing opposed adhesively treated portions ofcarton flaps together comprising a housing having a chamber formedtherein, a metallic nozzle bar means having at least one flat andsubstantially uninterrupted surface and a plurality of apertures formedtherein communicating with said chamber for discharging heated airtherethrough, heating means in said chamber and associated with saidnozzle bar means to conduct heat through metallic portions thereof suchthat said adhesively treated portions of said carton are heated by acombination of said heated air and heat conducted through the metallicportions of said nozzle bar means and means for applying pressure tosaid flaps to seal them together.

22. Apparatus according to claim 21 wherein said apparatus furthercomprises a plurality of fins constructed and arranged in said chamberto substantially surround and contact said heating means, and aplurality of slots formed between said fins and arranged to communicateair to said apertures after said air has been heated by said heatingmeans.

23. Apparatus according to claim 22 wherein said housing and said finsare further constructed and arranged to conduct heat from said heatingmeans to said nozzle bar means to heat and maintain the nozzle bar meansat a temperature which is substantially the same as the temperature ofthe air discharged from said apertures.

24. Apparatus according to claim 21 wherein said nozzle bar means iselongated and has first and second flat and substantially uninterruptedsurfaces terminating at a top edge of said nozzle bar means, saidplurality of apertures being formed in both said first and secondsurfaces, said apertures communicating with said chamber by passagemeans formed in said nozzle bar means.

References Cited UNITED STATES PATENTS 3,248,843 5/ 1966 Winters et al.53-373 X 3,249,024 5/ 1966 Shiu 156-497 X 3,336,464 8/ 1967 Hittenbergeret al. 156497 X 3,340,777 9/1967 Hittenberger et al. 53-375 X TRAVIS S.MCGEHEE, Primary Examiner U.S. Cl. X.R. 219 374

